This invention relates to a mechanical component consisting of anti-static material used for equipment, such as a copying machine, a facsimile machine, and an electrostatic plotter, which make copies or draw charts by means of static electricity, laser, or the like.
Since equipment such as a copying machine use electrostatic absorption, some mechanical components of the equipment that are made of synthetic resin require static-prevention measures. Other mechanical components including gears and pulleys do not have to be given such measures, because they are generally made of conductive metals.
Mechanical components, such as a drive belt and a driven belt including a V-belt and a timing belt, a roller and a flat belt for feeding paper, and a light carriages of a copying machine, need some elasticity and they are made of synthetic resin such as silicon rubber, hard rubber, or the like. Yet, since these synthetic resin mechanical components are insulating materials, they become charged with static electricity caused by friction. In order to prevent static electricity, these mechanical components contain conductive filler such as carbon black and metallic particles. However, these mechanical components endowed with conductivity by conductive filler have the following problems.
Mixing carbon black in a synthetic resin base material reduces the electric resistivity of the synthetic resin. However, at the same time the mechanical properties including strength of the synthetic resin are lowered. Therefore, only a limited amount of carbon black can be contained in the synthetic resin.
In addition, even if the synthetic resin includes the limited amount of the carbon black, other problems still remain. When the electric resistivity is between 10.sup.10 ohm.cm and 10.sup.3 ohm.cm, which is the optimum resistivity range for preventing static electricity (called "optimum electric resistivity" below), the resistivity suddenly becomes low by adding a very small quantity of the carbon black. So it is difficult to mix the carbon black in the synthetic resin so as to attain an optimum electric resistivity. As a result when copying paper that has electrostatically adsorbed toner is fed by a paper-feed roller of a copying machine, either static electricity on the paper-feed roller strips the toner from the paper or the paper sticks to the paper-feed roller.
Alternatively, when metallic particles are mixed in synthetic resin, the, metallic particles are apt to be randomly, or non-uniformly, dispersed because the specific gravity of the metallic particles is different from that of the synthetic resin. Therefore, mechanical components including metallic particles as a conductive filler have inconsistent electric resistivity.